Some subterranean equipment can be installed in boreholes for many years leaving an opportunity for debris to enter open cavities such as annular spaces between two structures that at some point need to move relatively to release or reconfigure the tool. If the debris accumulates in such spaces it has the capability of jamming the tool so that normal release is difficult if not impossible. A failure to normally release could cause the need for extraordinary and expensive measures such as a special trip to mill out the tool. Such measures are expensive and have the potential to cause other problems particularly if the generated debris from milling is not effectively removed with circulation or debris collection equipment that is in the hole.
Various designs for debris barriers have been used. A foam hollow cylinder that is mounted to an inner pipe and moved axially into a narrow annular space defined between an inner and outer tubulars is shown in FIGS. 5 and 6 of U.S. Pat. No. 8,464,787. Snap fit annular rings to go into an open annular space as a debris barrier are shown in U.S. Pat. No. 8,631,863. A foldable annular ring that employs a spring force to collapse for radial extension to protect an annular space between a string stabbed into a seal bore of a packer is shown in U.S. Pat. No. 7,604,048. Barriers that are internal to a tubular are shown in FIG. 4 of WO2013/122589. Another one-piece annular barrier is shown in FIG. 3 of EP 2322758 A2. Articulated tubular wipers that converge around a tubular as the tubular moves through where the wipers can be in single (104A) or multiple (not shown) semi-circular segments is shown in US 2013/0153302. This design is not for debris exclusion but rather is for forcibly scraping off debris from a tubular outer wall as the string is run into the borehole.
What is needed and provided by the present invention is a modular design where each module has a plurality of flexing resilient segments that can be scored or have gaps either when run in or after initial flexing where the gaps are circumferentially offset among the modules and the modules are rotationally locked to each other. The module spacing allows the segments to flex as much as 90 degrees or more before segments in one module contact segments in an adjacent module. The spacing allows fluid movement across the barrier while holding back the debris. These and other aspects of the present invention will be more readily apparent to those skilled in the art from a review of the detailed description and the associated drawings while recognizing that the full scope of the invention is to be determined from the appended claims.